# Tagged Questions

Questions about orbits with high eccentricities, which deviate greatly from perfect circles.

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### Determining effect of small variable force on planetary perihelion precession

Is there an analytical technique for determining the effect of a small variable transverse acceleration upon the rate of aspides precession (strictly not a precession but rotation of the line of ...
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### Are there a lot of collisions between stars in the core of the galaxy?

I'm reading on Wikipedia about Halo Stars that orbit the center of the galaxy at a high inclination away from the plane of the Milky Way. It seems that at some point, these stars must dive back into ...
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### Why Do Planets Revolve Faster When they Are Closer to Their Parent Star?

According to Kepler's second law: A planet sweeps out equal areas in equal times (A simple definition). This means that if the orbit is somewhat eccentric, the planet will move faster when on the ...
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### Why didn't Johannes Kepler use data about more planets?

In Astronomia Nova (1609) Johannes Kepler used observations of Mars in order to refute circular orbits. Throughout Astronomia Nova he hardly even mentions other planets than Mars, Earth and the Sun (...
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### Why do planets move in an elliptical orbit? [duplicate]

I am a student of class 9 and recently came to know about kepler's law of planetary motion and got confused about the foci and elliptical orbits of planets and some stars.
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### Orbital eccentricity variation of the other planets?

On Earth, it's fairly well published, mostly in climate change related articles, that the Earth's orbital eccentricity operates on a 413,000 year cycle with roughly 90,000 - 125,000 year variation ...
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### Orbiting and landing on non-sperical objects

If we orbit a non-spherical asteroid or moon at a sufficient distance I believe that we can consider it to be a point mass. Therefore we can take up a conventional orbit. Assuming our lander craft is ...
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### How did the moon's orbit become eccentric?

The Moon's orbit is more eccentric, 0.0549, than most planets. I can understand that planets get eccentric by disturbing each other like under the late heavy bombardment. And likewise for multiple ...
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### How does 'centre of mass' concept work?

We know that two celestial bodies rotate around a center of mass. How does this concept work in case of solar systems where there are several planets versus one/two stars? (Even if the center of mass ...